and()

🔗 Language Spec | Howto Guide

• A built-in function that accepts a list and returns the unification of all elements in the list

bool

🔗 Language Spec

• A primitive type representing the set of Boolean truth values denoted by the keywords true and false

Built-in functions

🔗 Language Spec

• Predeclared functions provided by the CUE runtime that are available without being imported
• see also: and() | close() | div() | mod() | len() | or() | quo() | rem()

bytes

🔗 Language Spec | Tour

• A primitive type representing a possibly empty sequence of arbitrary bytes

close()

🔗 Language Spec | Howto Guide

• A built-in function that converts a partially defined (“open”) struct to a fully defined (“closed”) struct

Default value

🔗 Tour | Howto Guide

• The single element of a disjunction that CUE assigns to a field if and only if unification fails to resolve a concrete value for the field
• An element of a disjunction prefixed with an asterisk (*)

Disjunction

🔗 Tour #1 | Tour #2

div()

🔗 Language Spec | Howto Guide

• A built-in function that performs Euclidean division with its parameters and returns the integer quotient

Field

🔗 Tour

• A key-value pair inside a map, associating a value with a given set of keys

Field constraint

🔗 Language Spec | Tour

• A field constraint restricts a field’s value without actually defining the field, with the field only forming part of the output if it is successfully unified with a concrete value
• see also: Required field constraint | Optional field constraint

float

🔗 Language Spec | Tour

• A primitive type representing the set of all decimal floating-point numbers

int

🔗 Language Spec | Tour

• A primitive type representing the set of all integer numbers

JSON

🔗 json.org

• “A lightweight data-interchange format … easy for humans to read and write [and] easy for machines to parse and generate.” – json.org
• A data format understood by the cue CLI, which can both parse and emit JSON as input and output

len()

🔗 Language Spec | Howto Guide

• A built-in function that returns the lengths of various types as an integer

List

🔗 Language Spec | Tour

• An arbitrary sequence of CUE values, enclosed in square brackets ([ ]) with values separated by commas (,)

mod()

🔗 Language Spec | Howto Guide

• A built-in function that performs Euclidean division with its parameters and returns the integer remainder

null

🔗 Language Spec

• A primitive type whose only value, the null value, is represented with the keyword null. Comparable with itself and any other type, the comparison with a null value always being equal and the comparison with any other type always being unequal

number

🔗 Language Spec | Tour

• A generic primitive type representing the set of all members of both int and float types

Optional field constraint

🔗 Tour | Howto Guide

• A field constraint that restricts the field’s value if the field is present, whilst also permitting the field’s absence

or()

🔗 Language Spec | Howto Guide

• A built-in function that accepts a list and produces a disjunction

quo()

🔗 Language Spec | Howto Guide

• A built-in function that performs truncated division with its parameters and returns the integer quotient

“Raw” strings

🔗 Language Spec | Tour

• A string literal enclosed with an equal number of hashes on both sides, allowing escape sequences to appear inside the text verbatim, without their usual escaping taking effect

rem()

🔗 Language Spec | Howto Guide

• A built-in function that performs truncated division with its parameters and returns the integer remainder

Required field constraint

🔗 Tour | Howto Guide

• A field constraint that restricts the field’s value whilst also requiring the field to be present

string

🔗 Language Spec | Tour

• A primitive type representing the set of UTF-8 strings
• see also: Raw strings

Struct

🔗 Language Spec | Tour

• A composite type representing a set of elements (called fields) each of which has a name (called a label) and a value

Type

🔗 Tour

Unification

🔗 Language Spec

YAML

🔗 yaml.org

• “YAML is a human-friendly data serialization language for all programming languages” – yaml.org
• A data format understood by the cue CLI, which can both parse and emit YAML as input and output